rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=900c/0/0x1 softirq=36326/36326 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9517/2:b..l rcu: (detected by 0, t=10506 jiffies, g=35397, q=291 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline] RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3820 [inline] RIP: 0010:validate_chain kernel/locking/lockdep.c:3876 [inline] RIP: 0010:__lock_acquire+0x83f/0x2630 kernel/locking/lockdep.c:5237 Code: ef e8 75 eb ff ff 8b 4c 24 08 85 c0 0f 85 6a fc ff ff e9 5d fb ff ff 0f b7 43 20 66 25 ff 1f 0f b7 c0 48 0f a3 05 a1 2a 2c 14 <0f> 83 b2 09 00 00 49 bc eb 83 b5 80 46 86 c8 61 4d 0f af e7 49 c1 RSP: 0018:ffffc90000a08c00 EFLAGS: 00000047 RAX: 0000000000000000 RBX: ffff88801e2bb0f8 RCX: 0000000000000001 RDX: 000000002cd708a8 RSI: 00000000e2f4bf9d RDI: 00000000c6b821bf RBP: ffff88801e2ba540 R08: 00000000e3c36222 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: cc889bfc2cd708a8 FS: 0000000000000000(0000) GS:ffff888124483000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33b23ffc CR3: 000000003f78a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b1/0x370 kernel/locking/lockdep.c:5825 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:166 debug_object_activate+0x144/0x490 lib/debugobjects.c:845 debug_hrtimer_activate kernel/time/hrtimer.c:485 [inline] debug_activate kernel/time/hrtimer.c:528 [inline] enqueue_hrtimer+0x75/0x2f0 kernel/time/hrtimer.c:1109 __run_hrtimer kernel/time/hrtimer.c:1946 [inline] __hrtimer_run_queues+0x73d/0xa00 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: b6 92 02 e9 43 44 03 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d e3 11 22 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197df0 EFLAGS: 00000246 RAX: 0000000000c820c5 RBX: ffff88801e2ba540 RCX: ffffffff8b898225 RDX: 0000000000000000 RSI: ffffffff8df0f8f1 RDI: ffffffff8c1c4680 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed10170a67b5 R10: ffff8880b8533dab R11: 0000000000000000 R12: 0000000000000001 R13: ffffed1003c574a8 R14: 0000000000000001 R15: ffffffff90d71150 arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x464/0x590 kernel/sched/idle.c:352 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:451 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x148 task:syz.1.984 state:X running task stack:26296 pid:9517 tgid:9509 ppid:0 task_flags:0x40044c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0x970 kernel/entry/common.c:164 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:rcu_preempt_read_exit kernel/rcu/tree_plugin.h:396 [inline] RIP: 0010:__rcu_read_unlock+0x1d/0x5e0 kernel/rcu/tree_plugin.h:435 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 41 55 41 54 55 53 65 48 8b 1d d2 e5 1b 12 48 8d bb c4 04 00 00 <48> b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 48 RSP: 0018:ffffc900055d7ad8 EFLAGS: 00000286 RAX: 0000000000000000 RBX: ffff88803537ca80 RCX: ffffc900055d7acc RDX: 0000000000000001 RSI: ffffffff8deea396 RDI: ffff88803537cf44 RBP: 0000000000000000 R08: 0000000000000001 R09: fffffbfff21ae22a R10: ffffffff90d71157 R11: 0000000000000000 R12: 00000000fffffffc R13: 0000000000000025 R14: ffff88813fffb100 R15: ffff88803537e330 mod_lruvec_state mm/memcontrol.c:973 [inline] lruvec_stat_mod_folio+0x251/0x2e0 mm/memcontrol.c:993 mod_lruvec_page_state include/linux/vmstat.h:528 [inline] account_kernel_stack kernel/fork.c:490 [inline] exit_task_stack_account+0xc8/0x200 kernel/fork.c:503 do_exit+0x1643/0x2af0 kernel/exit.c:1009 do_group_exit+0xd5/0x2a0 kernel/exit.c:1119 get_signal+0x20ff/0x2210 kernel/signal.c:3037 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x98/0x670 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x666/0x870 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f526919ce59 RSP: 002b:00007f526a024028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: fffffffffffffe00 RBX: 00007f5269416180 RCX: 00007f526919ce59 RDX: 000000000000057d RSI: 0000200000003200 RDI: 0000000000000009 RBP: 00007f5269232d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5269416218 R14: 00007f5269416180 R15: 00007ffd03cab7f8 rcu: rcu_preempt kthread starved for 10506 jiffies! g35397 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:27848 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 9526 Comm: syz.3.987 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x589/0x1700 kernel/smp.c:892 Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 39 84 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 63 0f 00 00 8b 45 08 31 RSP: 0018:ffffc9000603fa00 EFLAGS: 00000246 RAX: 0000000000080000 RBX: 0000000000000001 RCX: ffffc90006c5c000 RDX: 0000000000080000 RSI: ffffffff81fc2c27 RDI: ffff8880335b4a80 RBP: ffff8880b8540f80 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170a81f1 R14: 0000000000000001 R15: ffff8880b843c600 FS: 00007f0afdc146c0(0000) GS:ffff888124383000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000046030 CR3: 000000003f78a000 CR4: 00000000003526f0 Call Trace: clock_was_set+0x62b/0x870 kernel/time/hrtimer.c:999 do_adjtimex+0x302/0x370 kernel/time/timekeeping.c:2924 do_clock_adjtime kernel/time/posix-timers.c:1154 [inline] __do_sys_clock_adjtime+0x177/0x290 kernel/time/posix-timers.c:1166 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0afcd9ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0afdc14028 EFLAGS: 00000246 ORIG_RAX: 0000000000000131 RAX: ffffffffffffffda RBX: 00007f0afd015fa0 RCX: 00007f0afcd9ce59 RDX: 0000000000000000 RSI: 0000200000000340 RDI: 0000000000000000 RBP: 00007f0afce32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0afd016038 R14: 00007f0afd015fa0 R15: 00007ffd00b9fee8